I. Field
The present disclosure relates generally to communication, and more specifically to techniques for searching for signals in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A wireless device (e.g., a cellular phone) may be able to receive service from one or more wireless communication systems. Upon power up, the wireless device may search for signals from a system from which it may receive service. If a system is found, then the wireless device may register with the system. The wireless device may then actively communicate with the system or go into an idle mode if communication is not required. If the wireless device subsequently loses the system, then it may enter an out-of-service state and attempt to re-acquire a signal from which service may be obtained.
The wireless device may not have any knowledge of its operating environment while in the out-of-service state. The wireless device may not know whether or when it can re-acquire a signal since this may depend on various factors such as system deployment, user mobility, channel conditions, system loading, etc. The wireless device may consume a large amount of battery power if it continuously searches for signals while in the out-of-service state. This heavy battery power consumption may significantly reduce both standby time and talk time.